On Tue, Nov 16, 2010 at 9:55 AM, Pauli Virtanen pav@iki.fi wrote:
Tue, 16 Nov 2010 09:41:04 -0500, Darren Dale wrote: [clip]
That loop takes 0.33 seconds to execute, which is a good start. I need some help converting this example to return an actual numpy array. Could anyone please offer a suggestion?
Easiest way is probably to use ndarray buffers and resize them when needed. For example:
https://github.com/pv/scipy-work/blob/enh/interpnd-smooth/scipy/spatial/qhul...
Thank you Pauli. That makes it *incredibly* simple:
import time cimport numpy as np import numpy as np
cdef extern from 'stdlib.h': double atof(char*)
def test(): py_string = '100' cdef char* c_string = py_string cdef int i, j cdef double val i = 0 j = 2048*1200 cdef np.ndarray[np.float64_t, ndim=1] ret
ret_arr = np.empty((2048*1200,), dtype=np.float64) ret = ret_arr
d = time.time() while i<j: c_string = py_string ret[i] = atof(c_string) i += 1 ret_arr.shape = (1200, 2048) print ret_arr, ret_arr.shape, time.time()-d
The loop now takes only 0.11 seconds to execute. Thanks again.